Device for scanning and centering containers filled with a liquid

ABSTRACT

An analyzer is described including a mechanism for scanning containers having variable diameters arranged in a tray and filled with body fluids, and for fixing the container and tray relative to an aspiration station for purposes of centering the aspiration probe to the containers. The scanning and positional centering mechanism include two movable scanning elements and a sensor which is associated with both elements and can be activated by them. The scanning elements are arranged normal to a pivotable transporter providing a transport path for the containers and preferably by means of two spring elements, retained in initial positions towards the transport path. By pivoting the transporter from a tray track to a scanning station for the containers, the scanning elements are moved to end positions and the sensor produces a signal which will depend upon the diameter of the container as positioned at the scanning station. The container is thereby centered as well as fixed in a tray by way of the scanning element and associated spring element while the tray is also centered and fixed on the transport path. The signal length produced by scanning elements and detected by the sensor is fed to a microprocessor of a control unit and is used to control the position and dip-in speed of a proboscis of an aspirator when body fluid is removed from the container.

FIELD OF THE INVENTION

The invention relates to a device for scanning and centering containersof different diameters filled with a liquid and arranged in a tray, inparticular test tubes filled with body fluid and fed to an aspiratingstation for body fluids in an analyzer.

BACKGROUND OF THE INVENTION

Analyzers featuring automatic scanning and centering means for handlinga number of samples or body fluids are known.

A centering means for liquid containers of different diameters that arearranged in a cassette in a single row is known from EP-PA 0 159 346,said means being provided within the cassette in the form of activatormeans.

In connection with EP-PA 0 159 347, devices for scanning liquidcontainers in the area of a mixing and aspirating station are known withthe position--related to the transport path--of the liquid containerrelative to the aspirator being detected and the identificationsprovided on the liquid container being scanned through openings providedin the lateral wall of the cassette. The containers closed by means ofstoppers are transported horizontally and moved to an inclined positionfor liquid removal with the stopper pointing down. For liquid removalthe rubber stopper is pierced by a hollow needle of an aspirator.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a device of thegeneric type by means of which the different diameters of the containerscan be detected, the containers can be centered and fixed in apredetermined position in an aspirating station for body fluids, and thebody fluid can be completely removed from the containers regardless oftheir diameters. Moreover, the processing rate for the samples is to beincreased considerably in order to meet the requirements of a quick andreliable diagnosis.

The above object is attained in that the scanning means consists of twomovable scanning elements and a sensor that can be covered by saidelements.

More particularly, in accord with one aspect of the invention, there isprovided a device for centering an aspirating probe in containers ofliquid having a center axis, the containers being supported on a traymoved along a support track, the device comprising first positiondetector means for detecting the position of a container by physicalcontact, a sensor cooperating with the position detector, and means forgenerating a signal in response to the contact. The device is improvedin that it further includes second position detector means for detectingby contact variations in the position of the tray, and wherein thesensor is operative and positioned to detect both of the positiondetector means.

In accord with another aspect of the invention, there is provided adevice for positioning a container in a tray so that liquid can beaccurately aspirated from a centered container, the device comprisingfirst means for detecting and centering by contact a container in atray. The device is improved in that it further includes second meansfor centering and fixing by contact the location of a tray relative toan aspirator, the first and second means being constructed to cooperatetogether.

Expediently, the scanning elements can be moved individually or jointlyfrom an initial position to an end position. Such movement of thescanning elements is advantageously effected in succession.

The invention provides for the sensor to be covered in the initialposition by means of the first scanning element and in the end positionby means of the second scanning element. Moreover, the scanning elementsare advantageously used for centering and fixing the container in a trayand the tray itself on the transport path.

In accord with yet another aspect of the invention, there is provided amethod for centering an aspirator probe within a container of liquid,the probe being constructed to descend along an axis having a positionadjustable in a horizontal plane depending on the size of the containerand the position of the container, the method comprising the steps of

a) placing a container of liquid into a tray, the container having avariable diameter;

b) moving the tray and the container of liquid into a position in whichthe container can be intersected by the probe;

c) sensing and fixing the position of the tray within the horizontalplane and generating a first signal representative of the position;

d) sensing and fixing the center of a container in the tray andgenerating a second signal representative of the center, and

e) moving the probe so as to descend on a line coincident with thecenter.

Additional advantageous features of the invention will be apparent inthe drawings as well as the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top view of the device according to the inventioncomprising a input station, a transport path and two processingstations,

FIG. 2 shows an elevational view of the scanning means according to FIG.1 including a tray equipped with containers,

FIG. 3 is a cross-section view along the line A--A in FIG. 2illustrating the scanning means according to FIG. 1 comprising twoscanning elements and a sensor,

FIG. 4 shows a cross-section view along the line B--B in FIG. 3illustrating the scanning means according to FIG. 3,

FIG. 5 is a schematic block diagram of a control unit, and

FIGS. 6a and 6b show diagrams indicating the typical signals generatedby the sensor according to FIG. 3 in response to the diameters of twodifferent containers.

An analyzer illustrated in FIG. 1 consists of an input stationcomprising four tray tracks 45 arranged side by side for test tubes orelongated trays 5 carrying containers 4, and a transporter 40 which isformed as an elongated housing 42 and is pivotable about a fulcrum 41 soas to be aligned with any of the tray tracks 45 on a support 100.Transporter 40 provides a transport path 130 along its body.

Adjacent to the support 100 for tracks 45 is a zero position 134, whichas shown in FIG. 1 is in alignment with path 130. A sensor 46 is mountedon transporter 40, which senses means such as slots, not shown, todetermine that path 130 is aligned with position 134.

In accordance with the invention, the analyzer features at zero position134, a scanning station (depicted as datum [A]) having a scanning means1 for scanning the positions of a container 4 and a tray, the scanningmeans working in cooperation with an aspirating station 30 featuring anaspirator 35 including a proboscis 36 for removing body fluid from acontainer 4. Aspirating station 30 is arranged so that the path ofdescent of proboscis 36 intersects the scanning station 46 and thetransport path 130, respectively, about halfway down the transport path130.

The scanning means 1 is arranged adjacent the aspirating station 30 andaligned with its central axis 31 extending normal to the central axis ofthe transport path 130 when coincident with the zero position 134.

The transport path 130 is about twice as long as a tray 5.

A laterally guided and longitudinally displaceable tray movement member49 is arranged on the transporter 40 and connected to housing 42, saidmember being used for moving tray 5 from the input station 44 to theaspirating station 30 and back.

FIGS. 2-4 show the scanning means 1 with a tray 5 positioned ontransporter 40 and equipped with containers 4 as well as the traymovement member 49 and its drive elements and a pulse generator 110.

Tray 5 is in a position in which the vertically extending central axis 8of a container 4 is aligned with the center of the aspirating station 30and thus with the center of scanning means 1 along the longitudinal sideof transport path 130.

Furthermore, FIG. 2 illustrates drive elements for pivoting thetransporter 40 whose arrangement and mode of operation will be describedin the following.

Housing 42 of transporter 40 is substantially closed on all sides andconsists of a housing portion 90 of U-shaped cross-section and a bottomportion 91 of L-shaped cross-section which are connected such that anelongate opening 92 is formed.

With its lower end portion the tray movement member 49 extends throughthe said elongate opening 92 into the interior of housing 42 and isconnected to a toothed belt 93 arranged therein.

Below the bottom portion 91 a stepping motor 98 is arranged which bymeans of a drive gear 94 and a guide roller 95 drives the toothed belt93 and thus the tray movement member 49. An encoder wheel 111 is mountedon a drive shaft 96 driven by the toothed belt 93, the rotary movementof said wheel being sensed by a photoelectric switch 112. Encoder wheel111 and switch 112 represent the pulse generator 110.

At the upper end portion of the tray movement member 49 a hook 97 isarranged which upstream of guide post 37 extends horizontally beyond thecenterline of transporter 40 and for transporting tray 5 engages with aneyelet 124 arranged on the front face of tray 5.

Adjacent to the stepping motor 98 an additional stepping motor 114 ismounted to the bottom portion 91 and by means of a drive gear 101 and atoothed belt 102 drives a gear 103 for pivoting the transporter 40 abouta journal 104, i.e. fulcrum 41. A gear 103 engages an arcuate rack 104which in the area of the exits 43 of tray tracks 45 is connected to asupport plate 106.

On support plate 106 two supports 107 and 107' (see FIG. 1) are arrangedwhich are mounted to housing 42 of transporter 40 and during pivotablemovement of transporter 40 slide thereon.

Each of the exits 43 of tray tracks 45 is associated with a retainingmeans 108 which is operated by means of an electromagnet 109.

FIG. 3 shows scanning means 1 and tray 5 as well as one of thecontainers 4 having a lid 24. Scanning means 1 is comprised of a firstposition detector means 2, a second position detector means 3 and asensor 6 which are all arranged on a support member 20.

Furthermore, a support member 20 is provided with a cover 25 for themeans 2, 3 and the sensor 6, at the upper end portion of cover 25 avertically pivotable stripper 23 for lid 24 being mounted which in itsinoperative position exerts pressure on lid 24 by means of a pressurespring and in the area of the lid has a passageway for proboscis 36 ofthe aspirator 35 (see FIG. 1).

Means 2 preferably comprises a cylindrical pin 26 which at the endfacing container 4 is pointed and at the opposite end has a flag 27.Means 3 preferably comprises a guide member 28 and a flag 29, with saidguide member 28 having a bore in its horizontally extending longitudinalaxis 14 and flag 29 being arranged at the end portion as in the case ofmeans 2.

Guide member 28 which is shorter than pin 26 of means 2 is slideablysupported on pin 26 by means of its bore. At the side of the scanningmeans 1 facing container 4 guide member 28 is also supported by asupport means 15 under cover 25 of support member 20. Along thelongitudinal axis 14, pin 26 is also slideably supported by a supportmeans 16 of support member 20, said support means being arranged betweenflags 27 and 29.

The longitudinal axis 14 common to means 2 and 3 is in alignment withcenter axis 31 of aspirating station 30, that is to say normal to thevertically extending central axis 8 of container 4 and normal to thelongitudinal side of transport path 130 (see FIGS. 1 and 2).

Means 2 and 3 are arranged in the upper area of tray 5 and container 4,respectively. Pin 26 of means 2 extends through guide member 28,projects from scanning means 1 and further extends through an aperture121 provided in an exterior wall 120 of tray 5 (see FIG. 4). Pressure isthereby exerted on means 2 and 3 by means of spring elements 21, 22. Thetwo spring elements 21, 22 are designed as helical springs coaxiallysupported by pin 26. One end portion of inner spring element 21 rests onsupport means 16 and the other on washer 17 permanently connected to pin26. One end portion of the outer spring element 22 also rests on supportmeans 16 and the other on guide member 28.

In this representation, means 2 and 3 are shown in end positions 13 and13' determined by the diameter of container 4 and by the width of tray5.

The pressure forces of spring elements 21, 22 are dimensioned such thatcontainer 4 can be centered and fixed in a receptacle 122 of tray 5 andtray 5 itself can be centered and fixed with its widened base 123 ontransport path 40 by means of the guide posts 37 provided thereon. Forthis purpose, receptacle 123 of tray 5 is octagonal in cross-section andthus features for container 4 a prism-shaped nest in an exterior wall120' (see FIG. 1).

Furthermore, the spring elements 21 and 22 are dimensioned such thatmeans 2 and 3 are positioned in the initial positions 12 and 12' shownin dotted lines when transporter 40 has been pivoted out of scanningstation [A].

The initial positions 12 and 12' are thereby limited by means of flags27 and 29 as well as their positions relative to the support means 16and 15 associated therewith.

In the initial positions 12 and 12' means 2 projects beyond means 3 byan amount which is larger than the largest admissible radius of acontainer 4.

The flags 27 and 29 of means 2 and 3 are arranged one behind the otheralong the longitudinal axis 14 so as to be in alignment with each otherand extend vertically upwards into a scanning range of sensor 6.

As shown in the drawing, sensor 6 is covered by flag 29 of means 3positioned in its end position 13'.

If means 2 and 3 are positioned in the initial positions 12 and 12' whentransporter 40 has been pivoted out of scanning station [A], sensor 6 iscovered by flag 27 of means 2.

In FIG. 4 means 2, 3 and sensor 6 are shown in cross-section as seen inthe direction of their longitudinal axis 14 or in the direction ofcontainer 4 held in tray 5.

Pin 26 of means 2 and guide member 28 of means 3 are thereby centrallyaligned with the centerpoint of a widened portion 125 of an aperture 121in the exterior wall 120 of tray 5, the centerpoint being located oncentral axis 8 of container 4.

Widened portion 125 is arranged symmetrically to aperture 121 and has anoctagonal shape. Portion 125 as well as aperture 121 are limited bymeans of a flange 126 of exterior wall 120. The portion 125 has beenadapted to the dimensions of means 2 and 3 such that it is larger thanthe diameter of pin 26 but smaller than the outer diameter of guidemember 28.

As a result, guide member 28 partly covers flange 126 of portion 125 andrests thereon during the scanning procedure (see FIG. 3 and 4).

Sensor 6 is formed by an optoelectric interrupter switch. According totheir position along longitudinal axis 14, the flags 27 and 29 mountedat the upper end of means 2 and 3 extend into the scanning range ofsensor 6 and pass or interrupt the horizontally extending light beam(see FIG. 3).

The device operates as follows:

For step a) of the method of the Summary, one or several trays 5equipped with containers 4 or test tubes are inserted in one or all ofthe four tray tracks 45 of the input station 44. The individualcontainers 4 are filled with body fluid and generally closed by lids 24.

If now a processing procedure is started via a keyboard 51 of a controlunit 50 shown in FIG. 5, said procedure will proceed according to aprogram stored in a memory (ROM) 52 and in accordance with theprocessing instructions of memory (RAM) 53 in cooperation with amicroprocessor 55.

After starting the processing procedure, the transporter 40 driven bythe stepping motor 114 is pivoted to tray track 45 of input station 44holding a desired tray 5 with the containers 4 selected.

For step b) of the method set forth in the Summary, tray movement member49 driven by the stepping motor 98 is moved towards input station 44,with hook 97 engaging eyelet 124 of tray 5 as soon as transporter 40 hasreached the tray track 45 selected. When transporter 40 is in alignmentwith tray track 45, retaining means 108 is removed downwardly from theexit 43 and tray 5 together with the containers 4 is moved ontotransport path 130 by the tray movement member 49.

When tray 5 has completely moved onto transporter 40, the transporter ispivoted towards the zero position 134 and thus to the scanning means 1while tray 5, i.e. the container 4 selected, is simultaneously movedtowards the aspirating station 30. The position of container 4 along thetransport path 130 is detected in response to tray movement member 49 inthat the pulses produced by the pulse generator 110 in proportion to thelength of the transport path are counted by the control unit 50.

Pivoting of the transporter 40 and movement of tray 5 are controlled bymeans of control unit 50 such that the container 4 selected has reachedthe position of the aspirating station 30 on the transport path 130before the transport path moves into the line of the zero position 134.

For steps c) and d) of the method, when transporter 40 reaches the zeroposition 134 and the scanning means 1, first means 2 by means ofcontainer 4 and then means 3 by means of tray 5 are moved from theirinitial positions 12 and 12' to their end positions 13 and 13'. Pivotalmovement of transporter 40 is terminated as soon as container 4 isexactly positioned in aspirating station 30 as well as centered andfixed in tray 5 under the action of means 2 and 3.

During the pivotal movement the receiver element of sensor 6 is firstuncovered by flag 27 of means 2 and subsequently recovered by flag 29 ofmeans 3 when said means 3 has reached its end position 13'.

As shown in FIGS. 6a and 6b, the receiver element of sensor 6 produceswhile being uncovered a signal 62 having a high-level the length 60 ofwhich is determined by the diameter of the scanned container 4. Thismeans that a small diameter relative to a large one produces a shortersignal due to the receiver being uncovered by the means 2 somewhatlater, the end position 13' of means 3 being identical with bothdiameters.

For detecting the diameter (proportional to signal length 60), thestepping pulses 63 of stepping motor 114 of the pivot drive system arecounted by the microprocessor 55 of control unit 50 for the duration ofthe high-level signal 62 and stored in memory (RAM) 53.

Subsequently, for step e) of the method, aspirator 35 is activated bycontrol unit 50 for removal of body fluid from container 4 positioned atthe aspirating station 30.

Now the movement of proboscis 36 of aspirator 35 to the center of theopening 9 of container 4 and the dip-in speed and depth of proboscis 36into the body fluid are controlled in response to the number of steppingpulses 63.

Prior to dipping into the body fluid, proboscis 36 guided through anaperture of stripper 23 pierces the lid 24 placed on container 4.

After removal of body fluid, proboscis 36 is moved to its upper initialposition. During this upward movement the lid 24 clinging to theproboscis 36 is stripped off by the stripper 23 and replaced oncontainer 4. Body fluid adhering to proboscis 36 is thereby removed bymeans of the lid and returned into container 4.

When the proboscis 36 has been pivoted away, transporter 40 controlledby control unit 50 is pivoted out of the scanning station 46 and,according to the program, the next container 4 is moved to the positionof transport path 130 corresponding to the aspirating station 30.

During this procedure, transporter 40 is pivoted back to the zeroposition 134 and the above described process is repeated until therequired body fluids have been removed from all containers 4 of tray 5.

Then tray 5 containing the emptied containers 4 is returned to its traytrack 45 of input station 44 and the next tray 5 from a further traytrack 45 is moved onto the transporter 40.

If tray 5 is incorrectly equipped, that is to say if a container 4 ismissing, sensor 6 is not uncovered by means 2 and 3 and thus no signalis produced. This leads to an error message by the control unit 50indicated on a display panel 54 (see FIG. 5).

What is claimed is:
 1. In a device for centering an aspirating probe incontainers of liquid, said containers having a center axis, and beingsupported on a tray moved along a support track, said device comprisingfirst position detector means for detecting the position of a containerby physical contact, a sensor cooperating with said position detectormeans, and means for generating a signal in response to said contact,theimprovement wherein said device further comprises second positiondetector means for detecting by contact positional variations of saidtray, and wherein said sensor is operative and positioned to detect bothof said position detector means.
 2. A device as defined in claim 1,wherein said first and said second position detector means are movablefrom an initial position to an end position.
 3. A device according toclaim 2, wherein said sensor senses said first position detector meansin said initial position or said second position detector means in saidend position.
 4. A device according to claims 1 or 2, and furtherincluding a support member, both of said position detector means andsaid sensor being arranged on said support member.
 5. A device accordingto claim 2, wherein both said position detector means are arrangedadjacent the location of the upper region of a container and areoriented normal to its central axis.
 6. A device as defined in claims 1or 2, further including a movable aspirator and a movable transporterfor carrying trays to said aspirator along a transport path, saidposition detector means being located at a scanning station to whichsaid transporter is movable.
 7. A device according to claim 6, whereinboth of said position detector means are operably movable on a pathnormal to said tray transport path, said path of movement of saiddetector means being constructed to intersect the path of movement ofsaid aspirator.
 8. A device according to claim 6, and further includinga plurality of tray tracks for supporting a plurality of trays, saidtransporter being pivoted about a fulcrum that is an intersection pointof at least two of said tracks when extended along a said transportpath, so that a tray can be transported onto said transporter from atrack by pivoting said transporter into alignment with a selected one ofsaid tracks.
 9. A device according to claim 6, and further including asensor on said transporter and means cooperating with said sensor forgenerating a signal indicative of said transporter being in apredetermined zero position in which a tray on said transporter shouldbe in contact at said second position detector means.
 10. A device asdefined in claim 2, and further including biasing means for biasing bothsaid position detector means from said end position towards said initialposition.
 11. A device according to claim 2, wherein said containershave a diameter and said end position of said first detector means isdetermined by contact with the diameter of a container and said endposition of said second detector means is determined by contact with thewidth and position of a tray holding the container.
 12. A deviceaccording to claim 2, wherein in said initial position, said firstposition detector means extends beyond said second position detectormeans by an amount which is larger than a largest admissible radius of acontainer.
 13. Device according to claims 11, wherein the signalgenerated by said sensor depends on the diameter of a container.
 14. Adevice according to claim 6, wherein the signal of said sensor iscontrolled by movement of said transporter from a predetermined zeroposition.
 15. A device for positioning a container in a tray so thatliquid can be accurately aspirated by an aspirator from a centeredcontainer, said device comprising first means for detecting andcentering by physical contact said container in said tray, theimprovement wherein said device further includes second means forcentering and fixing by physical contact the location of said trayrelative to said aspirator, a sensor means for detecting and cooperatingsaid first and second means.